The present invention relates generally to laminated label sheets, and, more specifically, to label integrity thereof.
Label sheets are commonly available in various configurations with and without printing thereon. A typical label sheet is a laminate of a paper overlay and an underlying release liner. An adhesive bonds the overlay to the liner in the finished article.
In typical use, information is printed atop the overlay, and the overlay is then removed from the liner by being peeled therefrom. The peeled away label has exposed adhesive so that it may be pressed against paper or other object for attachment thereto. A typical release liner is coated over one side with liquid silicone which is thermally cured for providing a low adhesion surface thereatop to which the overlay is temporarily bonded. The adhesive provides a weak bond between the overlay and the silicone liner which sufficiently maintains together the laminate until it is desired to remove the overlay from the liner.
More complex label sheets include several labels or decals in the overlay defined by respective perimeter diecuts therebetween which allow removal of individual labels from the liner. The individual labels may be directly adjacent to each other or there may be an intervening label rim or border which remains attached to the liner after the individual labels are peeled away.
A further increase in complexity of the label sheet includes an integral paper form attached to the label portion of the overlay which does not overlie the liner. This type of label sheet may be manufactured using a lap joining method wherein the label and liner laminate is premanufactured and lap joined along an edge thereof to the paper form. In another, integrated, method of manufacture, the entire overlay, including the label and form portions thereof, is separately manufactured in a common sheet and the liner is then bonded below the label portion thereof.
These various label sheets nevertheless use a commonly fabricated release liner which is typically manufactured in large rolls with the silicone in liquid form being applied over the entire surface of the liner paper which is then thermally cured. The large roll of release liner is then cut into individual smaller rolls for use in various label sheet applications as required.
The release coating may be specifically formulated to effect low to high release bonds with the overlay. In use, it is desired to have low release bonds so that the individual labels may be easily removed. This is typically accomplished by bending the label sheet near one of the diecuts to locally break the bond thereat to expose a portion of the label which is then peeled away.
However, if the release bond is too weak, individual labels may separate from the liner during their travel through a laser printer for example. A laser printer may include narrow rollers for guiding the label sheet therethrough, and also includes a fusion roller for heat curing the printing toner on the labels. The heat softens the adhesive, and the narrow rollers bend the sheet tightly which can separate the labels from the liner if insufficient release bonds are used. If a label predispenses in the printer, it not only destroys the usefulness of the label, but can damage the printer by bonding to internal components thereof.
Accordingly, the release bond is typically tailored for a specific type of label sheet and intended printer, and should be suitably high to prevent predispensing in the printer. This correspondingly high release bond increases the difficulty of manually removing individual labels when desired in use. This can be a significant problem where labels are used in large volume, such as in the pharmacy industry.
Pharmacists typically use the combined label sheet and form for recording various information in a typical pharmaceutical drug transaction which requires one or more individual labels to be removed from the sheet and attached to a prescription drug container. The use of high release bonds in a label sheet to prevent predispensing in a laser printer correspondingly increases the difficulty of removing individual labels from the sheet, and therefore increases the amount of work and time required in completing individual drug transactions.
Accordingly, it is desired to provide an improved label sheet which increases the ease of removing individual labels during use, yet prevents predispensing thereof in a laser printer.
A label sheet includes a label joined to a release liner by an adhesive with adjacent relatively low and high release bonds. The high release bond secures the label to the liner, and the low release bond permits easy removal therefrom.